ACES Constraining masses of S-type AGB stars with pulsation - Yoshiya Mori (Monash)
The lowest initial mass at which the third dredge-up (TDU) occurs is a major uncertainty in stellar models of asymptotic giant branch (AGB) stars. Observations indicate that the minimum mass that we can expect a star to become a carbon star via TDU is ∼1.5 solar masses at solar
metallicity. However, the minimum mass is not well constrained, and lower mass stars may still experience episodes of TDU. AGB stars of spectral type S, which have C/O ratios between 0.5 to 1, are compelling cases to address this uncertainty. By estimating the masses of S-type AGB stars we can probe the lowest masses which experience TDU. In this study, we aim to derive
masses for a literature sample of Galactic S-type stars by measuring their pulsation periods from ASAS-SN light curves, and comparing their luminosities and pulsation periods with results from extant models of AGB evolution and pulsation. We also construct an initial mass function for
S-type AGB stars to provide further constraints on the minimum initial mass required for TDU.
